Electronic Message Centers 101

Reader boards, Digital signs, LED displays, Electronic message centers. They go by many different names but here at Holiday Signs we call them Electronic Message Centers to cover the many types of digital signs available on the market.

So, what is an LED sign? LED stands for “light emitting diode”. It is not a light bulb, it has no filament. It is an ultrabrite, energy efficient alternative that doesn’t burn out. You may have seen LED TV’s on the market recently, and an Electronic message board works the same way.

Pixels, Pitch, Viewing Angle, and The Matrix

Just like on your television, images are made up of many tiny dots known as pixels. In a color sign or television, each pixel is made up of red green and blue LEDs. In a monochrome or single color sign, each LED would be an individual pixel. A pixel is the smallest element of the electronic display that can be individually controlled.

tv_pixel1 EMC_pixels1
Here is a close up of an LED TV. As you can see each pixel is made up of 3 LEDs in an RGB configuration. By varying the intensity of the LED’s any color is possible. Here is a close up of an LED panel showing the same 3 RGB LED’s. Each grouping of RGB LED’s makes up one pixel.


Pitch, or dot pitch, is the distance between pixels. On a computer screen or television, you may express this in DPI or dots per inch. For Electronic Message Centers this is expressed in raw distance between pixels. So a sign that has a 16mm pitch has 16mm of space between pixels.

Since EMC’s are viewed from long distances, the pixels do not need to be as close together as your TV or computer monitor that you might view from only a foot away. In computer displays, common dot pitches are .31mm, .28mm, .27mm, .26mm, and .25mm. Traditional televisions often use a larger dot pitch, about .51 mm, and large screen TVs or projection devices can go up to 1 millimeter in pitch.

The smaller and closer the dots are to one another, the more realistic and detailed the picture appears. When the dots are farther apart, they become noticeable and make the image look grainier.


Viewing Angle

Another consideration is the viewing angle of the sign. Viewing angle, simply put is how far off to each side of the sign can the message still be read. You’re probably viewing this on a flat-panel computer monitor, to experience viewing angle simply look at your monitor from the side. As you move further to the side, you will notice that the brightness drops off considerably until you can barely see the image from an acute angle.


LED signs work much the same way. The viewing angle is the maximum angle that the sign is still legible from. A quality LED sign will have 140° of viewing angle which maintains the highest color accuracy and extends reading times.

The Matrix

The Matrix is the size of your sign in pixels. If you have a sign that is 800 pixels tall by 600 pixels wide, you have an 800×600 matrix. In computer terms you might think of this as resolution. The size of your matrix determines how many characters you can fit on a sign, or how many pixels you have to make graphics.

Wrapping Up

There’s a lot that goes in to purchasing the right EMC for your needs. That’s why we have sign professionals who are well versed in getting the right EMC for you. Contact us today to find out how an EMC can turn passers-by into profit and receive our free whitepaper “The ABC’s of EMC’s”.